My mom passed away from breast cancer in Nov 2013 at the age of 57. Her smart meter was installed about a year prior. Do I believe that microwaves had anything to do with it? Absolutely not!
For starters, all the research I've done says non-ionizing radiation CAN'T CAUSE CANCER! This is why you can get cancer from ultraviolet light (which is classified as ionizing radiation) but you can't get cancer from, say, green light (which is non-ionizing radiation) It comes down to basic physics...
Secondly, if radio frequency did cause harm, it's not the 0.6 watt transmitters on smart meters that are going to be the main culprits. I'd be looking at the 50,000+ watt transmitters used for things like weather/aircraft radar, radio stations, etc. These have been around since the '50s and earlier, and nobody has found any correlation with harm. (and yes, there have been countless studies) Don't give me any BS about analog vs. digital waveforms either, since most digitally encoded waveforms (QAM, PSK, etc) look look and act almost identical to analog waveforms.
Oh, and lastly, I should mention that my mom was diagnosed a year before the smart meter was installed. She fought the good fight for two years and the addition of a smart meter had zero effect on the outcome.